DE 102010010268 A1 discloses a hybrid drive system for a motor vehicle with an internal combustion engine, a stop-start automatic system, an electric machine, and a starting device for starting the internal combustion engine. The starting device has a starting motor in the form of a three-phase motor and a drive shaft with a pinion. A crankshaft of the internal combustion engine furthermore has a starting sprocket wheel. In order to start the internal combustion engine, a transmission of force is carried out from the pinion to the starting sprocket wheel. A transmission ratio of the gear wheel pairing comprising the pinion and the starting sprocket wheel lies in the range from 30 to 50 and a voltage level of the supply voltages of the starting device and the electric machine is substantially identical. In order to start the internal combustion engine, a current of the three-phase motor of the starting device is controlled so that, during starting of the internal combustion engine, teeth of the pinion always bear with a flank directed in the starting direction against a flank, directed counter to the starting direction, of teeth of the starting sprocket wheel.
However, the inventors herein have recognized an issue with the above approach. Due to the relatively large amount of torque required to crank the engine at cold ambient temperatures, the electric motor is unable to start the engine under all conditions, and thus the starting device is included to enable cold engine starts. However, the starting device adds additional weight and packaging space to the engine/hybrid module unit, increasing costs and reducing fuel economy.
Accordingly, a hybrid module is presented herein to at least partly address the above issues. In one example, a hybrid module for arrangement on an internal combustion engine, and configured for starting the internal combustion engine, includes an electric motor, for generating a torque, an output element connected in a torque-transmitting manner to the electric motor and positioned on an output axle, for transmission of the torque to a crankshaft of the internal combustion engine, and a magnetic transmission, the torque of the electric motor configured to be transmitted via the magnetic transmission to the output element.
The hybrid module according to the disclosure is configured for arrangement on an internal combustion engine and for starting the internal combustion engine. The hybrid module comprises an electric motor, for generating a torque, and an output element connected in a torque-transmitting manner to the electric motor and positioned on an output axle, for transmission of the torque to a crankshaft of the internal combustion engine. According to the disclosure, the hybrid module has a magnetic transmission, wherein the torque of the electric motor may be transmitted via the magnetic transmission to the output element.
An example magnetic transmission is disclosed in DE 4405701 A1, which shows a magnetic transmission with several parts which interact magnetically and are movable relative to one another, of which one is connected to a drive shaft, one is connected to an output shaft and one is fixed, the fields generated by the permanent magnets being modulated by magnetically soft, flow-conducting parts, of which at least one is a toothed iron yoke. Structures which generate magnetic fields on the side facing the iron yoke by means of permanent magnets, which magnetic fields have alternating North and South poles along the circumference, are located on both sides of the iron yoke. The structure has on one side p1 pairs of North and South poles, the iron yoke on the side facing this structure having Z1=p1±N teeth and N being an integer. The structure has on other side p2 pairs of North and South poles, the iron yoke on the side facing this structure having Z2=p2±M teeth, M being an integer and M being equal to N.
It is thus advantageously enabled to start the internal combustion engine with the electric motor of the hybrid module. A separate starter may be omitted which reduces costs and weight. The magnetic transmission has a high level of efficiency, is overload-proof, requires essentially no lubrication, runs with a very low level of noise, and is wear-free.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.